Delay-sensitive and delay-insensitive deconvolution perfusion-CT: similar ischemic core and penumbra volumes if appropriate threshold selected for each.

INTRODUCTION: Perfusion-CT (PCT) processing involves deconvolution, a mathematical operation that computes the perfusion parameters from the PCT time density curves and an arterial curve. Delay-sensitive deconvolution does not correct for arrival delay of contrast, whereas delay-insensitive deconvolution does. The goal of this study was to compare delay-sensitive and delay-insensitive deconvolution PCT in terms of delineation of the ischemic core and penumbra. METHODS: We retrospectively identified 100 patients with acute ischemic stroke who underwent admission PCT and CT angiography (CTA), a follow-up vascular study to determine recanalization status, and a follow-up noncontrast head CT (NCT) or MRI to calculate final infarct volume. PCT datasets were processed twice, once using delay-sensitive deconvolution and once using delay-insensitive deconvolution. Regions of interest (ROIs) were drawn, and cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT) in these ROIs were recorded and compared. Volume and geographic distribution of ischemic core and penumbra using both deconvolution methods were also recorded and compared. RESULTS: MTT and CBF values are affected by the deconvolution method used (p < 0.05), while CBV values remain unchanged. Optimal thresholds to delineate ischemic core and penumbra are different for delay-sensitive (145 % MTT, CBV 2 ml × 100 g(-1) × min(-1)) and delay-insensitive deconvolution (135 % MTT, CBV 2 ml × 100 g(-1) × min(-1) for delay-insensitive deconvolution). When applying these different thresholds, however, the predicted ischemic core (p = 0.366) and penumbra (p = 0.405) were similar with both methods. CONCLUSION: Both delay-sensitive and delay-insensitive deconvolution methods are appropriate for PCT processing in acute ischemic stroke patients. The predicted ischemic core and penumbra are similar with both methods when using different sets of thresholds, specific for each deconvolution method.

Assignment markets with the same core

[spa] En el contexto de los juegos de asignación bilaterales, estudiamos el conjunto de matrices asociadas a mercados de asignación con el mismo nucleo. Se proporcionan condiciones sobre las entradas de la matriz que aseguran que los juegos de asignación asociados tienen el mismo núcleo. Se prueba que este conjunto de matrices que dan lugar al mismo núcleo forman un semirretículo con un número finito de elementos minimales y un único máximo. Se da una caracterización de estos elementos minimales. También se proporciona una condición suficiente para obtener un retículo.

Multi-sided Böhm-Bawerk assignment markets: the core

[cat] En aquest treball introduïm la classe de "multi-sided Böhm-Bawerk assignment games", que generalitza la coneguda classe de jocs d’assignació de Böhm-Bawerk bilaterals a situacions amb un nombre arbitrari de sectors. Trobem els extrems del core de qualsevol multi-sided Böhm-Bawerk assignment game a partir d’un joc convex definit en el conjunt de sectors enlloc del conjunt de venedors i compradors. Addicionalment estudiem quan el core d’aquests jocs d’assignació és estable en el sentit de von Neumann-Morgenstern.

Consistency and the core of multi-sided assignment markets

[cat] En aquest treball es demostra que en el domini dels jocs d’assignació equilibrats multisectorials (Quint, 1991), el core és l’única solució no buida que satisfà derived consistency i projection consistency. També es caracteritza el core en tota la classe dels jocs d’assignació multisectorials amb els axiomes de singleness best, individual antimonotonicity i derived consistency. Com a casos particulars, s’obtenen dues noves axiomàtiques del core per als jocs d’assignació bilaterals (Shapley and Shubik, 1972).

Coronary vasomotor responses to isometric handgrip exercise are primarily mediated by nitric oxide: a noninvasive MRI test of coronary endothelial function.

Endothelial cell release of nitric oxide (NO) is a defining characteristic of nondiseased arteries, and abnormal endothelial NO release is both a marker of early atherosclerosis and a predictor of its progression and future events. Healthy coronaries respond to endothelial-dependent stressors with vasodilatation and increased coronary blood flow (CBF), but those with endothelial dysfunction respond with paradoxical vasoconstriction and reduced CBF. Recently, coronary MRI and isometric handgrip exercise (IHE) were reported to noninvasively quantify coronary endothelial function (CEF). However, it is not known whether the coronary response to IHE is actually mediated by NO and/or whether it is reproducible over weeks. To determine the contribution of NO, we studied the coronary response to IHE before and during infusion of N(G)-monomethyl-l-arginine (l-NMMA, 0.3 mg·kg(-1)·min(-1)), a NO-synthase inhibitor, in healthy volunteers. For reproducibility, we performed two MRI-IHE studies ∼8 wk apart in healthy subjects and patients with coronary artery disease (CAD). Changes from rest to IHE in coronary cross-sectional area (%CSA) and diastolic CBF (%CBF) were quantified. l-NMMA completely blocked normal coronary vasodilation during IHE [%CSA, 12.9 ± 2.5 (mean ± SE, placebo) vs. -0.3 ± 1.6% (l-NMMA); P < 0.001] and significantly blunted the increase in flow [%CBF, 47.7 ± 6.4 (placebo) vs. 10.6 ± 4.6% (l-NMMA); P < 0.001]. MRI-IHE measures obtained weeks apart strongly correlated for CSA (P < 0.0001) and CBF (P < 0.01). In conclusion, the normal human coronary vasoactive response to IHE is primarily mediated by NO. This noninvasive, reproducible MRI-IHE exam of NO-mediated CEF promises to be useful for studying CAD pathogenesis in low-risk populations and for evaluating translational strategies designed to alter CAD in patients.

Assignment markets with the same core

[spa] En el contexto de los juegos de asignación bilaterales, estudiamos el conjunto de matrices asociadas a mercados de asignación con el mismo nucleo. Se proporcionan condiciones sobre las entradas de la matriz que aseguran que los juegos de asignación asociados tienen el mismo núcleo. Se prueba que este conjunto de matrices que dan lugar al mismo núcleo forman un semirretículo con un número finito de elementos minimales y un único máximo. Se da una caracterización de estos elementos minimales. También se proporciona una condición suficiente para obtener un retículo.

Multi-sided Böhm-Bawerk assignment markets: the core

[cat] En aquest treball introduïm la classe de "multi-sided Böhm-Bawerk assignment games", que generalitza la coneguda classe de jocs d’assignació de Böhm-Bawerk bilaterals a situacions amb un nombre arbitrari de sectors. Trobem els extrems del core de qualsevol multi-sided Böhm-Bawerk assignment game a partir d’un joc convex definit en el conjunt de sectors enlloc del conjunt de venedors i compradors. Addicionalment estudiem quan el core d’aquests jocs d’assignació és estable en el sentit de von Neumann-Morgenstern.

Consistency and the core of multi-sided assignment markets

[cat] En aquest treball es demostra que en el domini dels jocs d’assignació equilibrats multisectorials (Quint, 1991), el core és l’única solució no buida que satisfà derived consistency i projection consistency. També es caracteritza el core en tota la classe dels jocs d’assignació multisectorials amb els axiomes de singleness best, individual antimonotonicity i derived consistency. Com a casos particulars, s’obtenen dues noves axiomàtiques del core per als jocs d’assignació bilaterals (Shapley and Shubik, 1972).

Investigation of interface between Multimedia IP Network and Call Processing Server in 3G IP Telephony Core Network

The thesis presents an overview of third generation of IP telephony. The architecture of 3G IP Telephony and its components are described. The main goal of the thesis is to investigate the interface between the Call Processing Server and Multimedia IP Networks. The interface functionality, proposed protocol stack and a general description are presented in the thesis. To provide useful services, 3G IP Telephony requires a set of control protocols for connection establishment, capabilities exchange and conference control. The Session Initiation Protocol (SIP) and the H.323 are two protocols that meet these needs. In the thesis these two protocols are investigated and compared in terms of Complexity, Extensibility, Scalability, Services, Resource Utilization and Management.

Two cilengitide regimens in combination with standard treatment for patients with newly diagnosed glioblastoma and unmethylated MGMT gene promoter: results of the open-label, controlled, randomized phase II CORE study.

BACKGROUND: Survival outcomes for patients with glioblastoma remain poor, particularly for patients with unmethylated O(6)-methylguanine-DNA methyltransferase (MGMT) gene promoter. This phase II, randomized, open-label, multicenter trial investigated the efficacy and safety of 2 dose regimens of the selective integrin inhibitor cilengitide combined with standard chemoradiotherapy in patients with newly diagnosed glioblastoma and an unmethylated MGMT promoter. METHODS: Overall, 265 patients were randomized (1:1:1) to standard cilengitide (2000 mg 2×/wk; n = 88), intensive cilengitide (2000 mg 5×/wk during wk 1-6, thereafter 2×/wk; n = 88), or a control arm (chemoradiotherapy alone; n = 89). Cilengitide was administered intravenously in combination with daily temozolomide (TMZ) and concomitant radiotherapy (RT; wk 1-6), followed by TMZ maintenance therapy (TMZ/RT→TMZ). The primary endpoint was overall survival; secondary endpoints included progression-free survival, pharmacokinetics, and safety and tolerability. RESULTS: Median overall survival was 16.3 months in the standard cilengitide arm (hazard ratio [HR], 0.686; 95% CI: 0.484, 0.972; P = .032) and 14.5 months in the intensive cilengitide arm (HR, 0.858; 95% CI: 0.612, 1.204; P = .3771) versus 13.4 months in the control arm. Median progression-free survival assessed per independent review committee was 5.6 months (HR, 0.822; 95% CI: 0.595, 1.134) and 5.9 months (HR, 0.794; 95% CI: 0.575, 1.096) in the standard and intensive cilengitide arms, respectively, versus 4.1 months in the control arm. Cilengitide was well tolerated. CONCLUSIONS: Standard and intensive cilengitide dose regimens were well tolerated in combination with TMZ/RT→TMZ. Inconsistent overall survival and progression-free survival outcomes and a limited sample size did not allow firm conclusions regarding clinical efficacy in this exploratory phase II study.

Effects of exercise on mitochondrial DNA content in skeletal muscle of patients with COPD

Background Exhausting exercise reduces the mitochondrial DNA (mtDNA) content in the skeletal muscle of healthy subjects due to oxidative damage. Since patients with chronic obstructive pulmonary disease (COPD) suffer enhanced oxidative stress during exercise, it was hypothesised that the mtDNA content will be further reduced. Objective To investigate the effects of exercise above and below the lactate threshold (LT) on the mtDNA content of skeletal muscle of patients with COPD. Methods Eleven patients with COPD (676 8 years; forced expiratory volume in 1s (FEV1)456 8%ref) and 10 healthy controls (666 4 years; FEV1 906 7% ref) cycled 45 min above LT (65% peak oxygen uptake (V9O2 peak)and another 7 patients (656 6 years; FEV1 506 4%ref)and 7 controls (566 9 years;FEV1 926 6%ref) cycled 45 min below their LT (50% V9O2 peak). Biopsies from the vastus lateralis muscle were obtained before exercise, immediately after and 1 h, 1 day and 1 week later to determine by PCR the mtDNA/nuclear DNA (nDNA) ratio (a marker of mtDNA content) and the expression of the peroxisome proliferator-activated receptor- g coactivator-1 a (PGC-1a)mRNA and the amount of reactive oxygen species produced during exercise was estimated from total V9O2. Results Skeletal muscle mtDNA/nDNA fell significantly after exercise above the LT both in controls and in patients with COPD, but the changes were greater in those with COPD. These changes correlated with production of reactive oxygen species, increases in manganese superoxide dismutase and PGC-1 a mRNA and returned to baseline values 1 week later. This pattern of response wa was also observed, albeit minimised, in patients exercising below the LT. Conclusions In patients with COPD, exercise enhances the decrease in mtDNA content of skeletal muscle and the expression of PGC-1 a mRNA seen in healthy subjects probably due to oxidative stress.

Historical trends of organochlorine pesticides in a sediment core from the Gulf of Batabanó, Cuba.

Sediments can be natural archives to reconstruct the history of pollutant inputs into coastal areas. This is important to improve management strategies and evaluate the success of pollution control measurements. In this work, the vertical distribution of organochlorine pesticides (DDTs, Lindane, HCB, Heptachlor, Aldrin and Mirex) was determined in a sediment core collected from the Gulf of Batabanó, Cuba, which was dated by using the (210)Pb dating method and validated with the (239,240)Pu fallout peak. Results showed significant changes in sediment accumulation during the last 40 years: recent mass accumulation rates (0.321 g cm(-2) yr(-1)) double those estimated before 1970 (0.15 g cm(-2) yr(-1)). This change matches closely land use change in the region (intense deforestation and regulation of the Colon River in the late 1970s). Among pesticides, only DDTs isomers, Lindane and HCB were detected, and ranged from 0.029 to 0.374 ng g(-1) dw for DDTs, from<0.006 to 0.05 ng g(-1) dw for Lindane and from<0.04 to 0.134 ng g(-1) dw for HCB. Heptachlor, Aldrin and Mirex were below the detection limits (∼0.003 ng g(-1)), indicating that these compounds had a limited application in the Coloma watershed. Pesticide contamination was evident since the 1970s. DDTs and HCB records showed that management strategies, namely the banning the use of organochlorine contaminants, led to a concentration decline. However, Lindane, which was restricted in 1990, can still be found in the watershed. According to NOAA guidelines, pesticides concentrations encountered in these sediments are low and probably not having an adverse effect on sediment dwelling organisms.

Comparação entre fragmentos obtidos com agulhas de calibres 14 e 12 em "core biopsy" estereotáxica de lesões mamárias impalpáveis: diferenças entre o tamanho dos fragmentos e freqüência dos tipos de lesões diagnosticadas

Com o objetivo de avaliar o desempenho das agulhas de calibres 14 e 12 na obtenção de "core biopsies" da mama sob controle estereotáxico, os autores compararam biópsias de lesões mamárias impalpáveis obtidas com agulhas desses calibres quanto ao tamanho dos fragmentos e freqüência dos tipos de lesões diagnosticadas. De um total de 1.009 biópsias, os autores analisaram 900 obtidas por agulhas 14 e 109 obtidas por agulhas 12, para análise da freqüência das lesões. Os tamanhos dos fragmentos foram analisados nos 700 primeiros casos para os espécimes obtidos por agulhas 14. A utilização de agulhas 12 resultou em maior tamanho dos fragmentos (p < 0,001), ausência de material insatisfatório, redução na proporção das lesões benignas não-neoplásicas (p = 0,03) e aumento na freqüência de carcinomas (p < 0,001), tanto in situ como invasivos. Tais achados podem refletir aumento da acurácia do diagnóstico, em virtude da maior quantidade de material e/ou melhor seleção radiológica das biópsias obtidas por agulhas 12, pela utilização coincidente da mamografia digital em campo limitado (estereotaxia digital).

Effect of aerobic exercise on skeletal muscle mitochondrial content and function in older adults

Regular aerobic exercise training, which is touted as a way to ameliorate metabolic diseases, increases aerobic capacity. Aerobic capacity usually declines with advanced age. The decline in aerobic capacity is typically associated by a decrease in the quality of skeletal muscle. At the molecular level, this decreased quality comes in part from perturbations in skeletal muscle mitochondria. Of particular is a decrease in the total amount of mitochondria that occupy the skeletal muscle volume. What is not well established is if this decrease in mitochondrial content is due to inactive lifestyle or the process of aging. Herein, the work of the thesis shows a clear connection between mitochondrial content and aerobic capacity. This indicates that active individuals with higher VChmax levels also contain higher volumes of mitochondria inside their muscle as opposed to sedentary counterparts who have lower levels of mitochondrial content. Upon taking these previously sedentary individuals and entering them into an aerobic exercise intervention, they are able to recover their mitochondrial content as well as function to similar levels of lifelong athletes of the same age. Furthermore, the results of this thesis show that mitochondrial content and function also correlate with exercise efficiency. If one is more efficient, he/she is able to expend less energy for a similar power output. Furthermore, individuals who increase in efficiency also increase in the ability to oxidize and utilize fat during pro-longed exercise. This increased reliance on fat after the intervention is associated with an increased amount of mitochondria, particularly in the intermyofibrillar region of skeletal muscle. Therefore, elderly adults who were once sedentary were able to recover mitochondrial content and function and are able to reap other health benefits from regular aerobic exercise training. Aging per se does not seem to be the culprit that will lead to metabolic diseases but rather it seems to be a lack of physical activity. -- Un entraînement sportif d'endurance, connu pour réduire le risque de développer des maladies métaboliques, augmente notre capacité aérobie. La capacité aérobie diminue généralement avec l'âge. Ce déclin est typiquement associé d'une diminution de la qualité du muscle squelettique. Au niveau moléculaire, cette diminution est due à des perturbations dans les mitochondries du muscle squelettique,, ce qui conduit à une diminution de la quantité totale des mitochondries présentes dans le muscle squelettique. Il n'a pas encore été établi si cette diminution de la teneur mitochondriale est due à un mode de vie sédentaire ou au processus du vieillissement. Ce travail de thèse montre un lien clair entre le contenu mitochondrial et la capacité aérobie. Il indique que des personnes âgées actives, avec des niveaux de V02max plus élevés, possèdent également un volume plus élevé de mitochondries dans leurs muscles en comparaison à leurs homologues sédentaires. En prenant des individus sédentaires et leur faisant pratiquer une activité physique aérobie, il est possible d'accroître leur contenu de même que leur fonction mitochondriale à des niveaux similaires à ceux d'athlètes du même âge ayant pratiqué une activité physique tout au long de leur vie. De plus, les résultats de ce travail démontrent que le contenu et la fonction mitochondriale sont en corrélation avec l'efficiscience lors d'exercice physique. En agumentant l'effiscience, les personnes sont alors capables de dépenser moins d'énergie pour une puissance d'exercice similaire. Donc, un volume mitochondrial accru dans le muscle squelettique, associé à une fonction mitochondriale améliorée, est associté à une augmentation de l'effiscience. En outre, les personnes qui augmentent leur effiscience, augmentent aussi leur capacité à oxyder les graisses durant l'exercice prolongé. Une augmentation du recours au graisses après l'intervention est associée à une quantité accrue de mitochondries, en particulier dans la région inter-myofibrillaire du muscle squelettique. Par conséquent, les personnes âgées autrefois sédentaires sont en mesure de récupérer leur contenu et leur fonction mitochondriale ainsi que d'autres avantages pour la santé grâce à un entraînement aérobie régulier. Le vieillissement en soi ne semble donc pas être le coupable conduisant aux maladies métaboliques qui semblent plutôt être lié à un manque d'activité physique.